… | |
… | |
26 | puts ("stdin ready"); |
26 | puts ("stdin ready"); |
27 | // for one-shot events, one must manually stop the watcher |
27 | // for one-shot events, one must manually stop the watcher |
28 | // with its corresponding stop function. |
28 | // with its corresponding stop function. |
29 | ev_io_stop (EV_A_ w); |
29 | ev_io_stop (EV_A_ w); |
30 | |
30 | |
31 | // this causes all nested ev_loop's to stop iterating |
31 | // this causes all nested ev_run's to stop iterating |
32 | ev_unloop (EV_A_ EVUNLOOP_ALL); |
32 | ev_break (EV_A_ EVBREAK_ALL); |
33 | } |
33 | } |
34 | |
34 | |
35 | // another callback, this time for a time-out |
35 | // another callback, this time for a time-out |
36 | static void |
36 | static void |
37 | timeout_cb (EV_P_ ev_timer *w, int revents) |
37 | timeout_cb (EV_P_ ev_timer *w, int revents) |
38 | { |
38 | { |
39 | puts ("timeout"); |
39 | puts ("timeout"); |
40 | // this causes the innermost ev_loop to stop iterating |
40 | // this causes the innermost ev_run to stop iterating |
41 | ev_unloop (EV_A_ EVUNLOOP_ONE); |
41 | ev_break (EV_A_ EVBREAK_ONE); |
42 | } |
42 | } |
43 | |
43 | |
44 | int |
44 | int |
45 | main (void) |
45 | main (void) |
46 | { |
46 | { |
… | |
… | |
56 | // simple non-repeating 5.5 second timeout |
56 | // simple non-repeating 5.5 second timeout |
57 | ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.); |
57 | ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.); |
58 | ev_timer_start (loop, &timeout_watcher); |
58 | ev_timer_start (loop, &timeout_watcher); |
59 | |
59 | |
60 | // now wait for events to arrive |
60 | // now wait for events to arrive |
61 | ev_loop (loop, 0); |
61 | ev_run (loop, 0); |
62 | |
62 | |
63 | // unloop was called, so exit |
63 | // unloop was called, so exit |
64 | return 0; |
64 | return 0; |
65 | } |
65 | } |
66 | |
66 | |
… | |
… | |
292 | |
292 | |
293 | =back |
293 | =back |
294 | |
294 | |
295 | =head1 FUNCTIONS CONTROLLING THE EVENT LOOP |
295 | =head1 FUNCTIONS CONTROLLING THE EVENT LOOP |
296 | |
296 | |
297 | An event loop is described by a C<struct ev_loop *> (the C<struct> |
297 | An event loop is described by a C<struct ev_loop *> (the C<struct> is |
298 | is I<not> optional in this case, as there is also an C<ev_loop> |
298 | I<not> optional in this case unless libev 3 compatibility is disabled, as |
299 | I<function>). |
299 | libev 3 had an C<ev_loop> function colliding with the struct name). |
300 | |
300 | |
301 | The library knows two types of such loops, the I<default> loop, which |
301 | The library knows two types of such loops, the I<default> loop, which |
302 | supports signals and child events, and dynamically created loops which do |
302 | supports signals and child events, and dynamically created event loops |
303 | not. |
303 | which do not. |
304 | |
304 | |
305 | =over 4 |
305 | =over 4 |
306 | |
306 | |
307 | =item struct ev_loop *ev_default_loop (unsigned int flags) |
307 | =item struct ev_loop *ev_default_loop (unsigned int flags) |
308 | |
308 | |
… | |
… | |
606 | Like C<ev_default_destroy>, but destroys an event loop created by an |
606 | Like C<ev_default_destroy>, but destroys an event loop created by an |
607 | earlier call to C<ev_loop_new>. |
607 | earlier call to C<ev_loop_new>. |
608 | |
608 | |
609 | =item ev_default_fork () |
609 | =item ev_default_fork () |
610 | |
610 | |
611 | This function sets a flag that causes subsequent C<ev_loop> iterations |
611 | This function sets a flag that causes subsequent C<ev_run> iterations |
612 | to reinitialise the kernel state for backends that have one. Despite the |
612 | to reinitialise the kernel state for backends that have one. Despite the |
613 | name, you can call it anytime, but it makes most sense after forking, in |
613 | name, you can call it anytime, but it makes most sense after forking, in |
614 | the child process (or both child and parent, but that again makes little |
614 | the child process (or both child and parent, but that again makes little |
615 | sense). You I<must> call it in the child before using any of the libev |
615 | sense). You I<must> call it in the child before using any of the libev |
616 | functions, and it will only take effect at the next C<ev_loop> iteration. |
616 | functions, and it will only take effect at the next C<ev_run> iteration. |
617 | |
617 | |
618 | Again, you I<have> to call it on I<any> loop that you want to re-use after |
618 | Again, you I<have> to call it on I<any> loop that you want to re-use after |
619 | a fork, I<even if you do not plan to use the loop in the parent>. This is |
619 | a fork, I<even if you do not plan to use the loop in the parent>. This is |
620 | because some kernel interfaces *cough* I<kqueue> *cough* do funny things |
620 | because some kernel interfaces *cough* I<kqueue> *cough* do funny things |
621 | during fork. |
621 | during fork. |
622 | |
622 | |
623 | On the other hand, you only need to call this function in the child |
623 | On the other hand, you only need to call this function in the child |
624 | process if and only if you want to use the event loop in the child. If you |
624 | process if and only if you want to use the event loop in the child. If |
625 | just fork+exec or create a new loop in the child, you don't have to call |
625 | you just fork+exec or create a new loop in the child, you don't have to |
626 | it at all. |
626 | call it at all (in fact, C<epoll> is so badly broken that it makes a |
|
|
627 | difference, but libev will usually detect this case on its own and do a |
|
|
628 | costly reset of the backend). |
627 | |
629 | |
628 | The function itself is quite fast and it's usually not a problem to call |
630 | The function itself is quite fast and it's usually not a problem to call |
629 | it just in case after a fork. To make this easy, the function will fit in |
631 | it just in case after a fork. To make this easy, the function will fit in |
630 | quite nicely into a call to C<pthread_atfork>: |
632 | quite nicely into a call to C<pthread_atfork>: |
631 | |
633 | |
… | |
… | |
643 | Returns true when the given loop is, in fact, the default loop, and false |
645 | Returns true when the given loop is, in fact, the default loop, and false |
644 | otherwise. |
646 | otherwise. |
645 | |
647 | |
646 | =item unsigned int ev_iteration (loop) |
648 | =item unsigned int ev_iteration (loop) |
647 | |
649 | |
648 | Returns the current iteration count for the loop, which is identical to |
650 | Returns the current iteration count for the event loop, which is identical |
649 | the number of times libev did poll for new events. It starts at C<0> and |
651 | to the number of times libev did poll for new events. It starts at C<0> |
650 | happily wraps around with enough iterations. |
652 | and happily wraps around with enough iterations. |
651 | |
653 | |
652 | This value can sometimes be useful as a generation counter of sorts (it |
654 | This value can sometimes be useful as a generation counter of sorts (it |
653 | "ticks" the number of loop iterations), as it roughly corresponds with |
655 | "ticks" the number of loop iterations), as it roughly corresponds with |
654 | C<ev_prepare> and C<ev_check> calls - and is incremented between the |
656 | C<ev_prepare> and C<ev_check> calls - and is incremented between the |
655 | prepare and check phases. |
657 | prepare and check phases. |
656 | |
658 | |
657 | =item unsigned int ev_depth (loop) |
659 | =item unsigned int ev_depth (loop) |
658 | |
660 | |
659 | Returns the number of times C<ev_loop> was entered minus the number of |
661 | Returns the number of times C<ev_run> was entered minus the number of |
660 | times C<ev_loop> was exited, in other words, the recursion depth. |
662 | times C<ev_run> was exited, in other words, the recursion depth. |
661 | |
663 | |
662 | Outside C<ev_loop>, this number is zero. In a callback, this number is |
664 | Outside C<ev_run>, this number is zero. In a callback, this number is |
663 | C<1>, unless C<ev_loop> was invoked recursively (or from another thread), |
665 | C<1>, unless C<ev_run> was invoked recursively (or from another thread), |
664 | in which case it is higher. |
666 | in which case it is higher. |
665 | |
667 | |
666 | Leaving C<ev_loop> abnormally (setjmp/longjmp, cancelling the thread |
668 | Leaving C<ev_run> abnormally (setjmp/longjmp, cancelling the thread |
667 | etc.), doesn't count as "exit" - consider this as a hint to avoid such |
669 | etc.), doesn't count as "exit" - consider this as a hint to avoid such |
668 | ungentleman behaviour unless it's really convenient. |
670 | ungentleman-like behaviour unless it's really convenient. |
669 | |
671 | |
670 | =item unsigned int ev_backend (loop) |
672 | =item unsigned int ev_backend (loop) |
671 | |
673 | |
672 | Returns one of the C<EVBACKEND_*> flags indicating the event backend in |
674 | Returns one of the C<EVBACKEND_*> flags indicating the event backend in |
673 | use. |
675 | use. |
… | |
… | |
682 | |
684 | |
683 | =item ev_now_update (loop) |
685 | =item ev_now_update (loop) |
684 | |
686 | |
685 | Establishes the current time by querying the kernel, updating the time |
687 | Establishes the current time by querying the kernel, updating the time |
686 | returned by C<ev_now ()> in the progress. This is a costly operation and |
688 | returned by C<ev_now ()> in the progress. This is a costly operation and |
687 | is usually done automatically within C<ev_loop ()>. |
689 | is usually done automatically within C<ev_run ()>. |
688 | |
690 | |
689 | This function is rarely useful, but when some event callback runs for a |
691 | This function is rarely useful, but when some event callback runs for a |
690 | very long time without entering the event loop, updating libev's idea of |
692 | very long time without entering the event loop, updating libev's idea of |
691 | the current time is a good idea. |
693 | the current time is a good idea. |
692 | |
694 | |
… | |
… | |
694 | |
696 | |
695 | =item ev_suspend (loop) |
697 | =item ev_suspend (loop) |
696 | |
698 | |
697 | =item ev_resume (loop) |
699 | =item ev_resume (loop) |
698 | |
700 | |
699 | These two functions suspend and resume a loop, for use when the loop is |
701 | These two functions suspend and resume an event loop, for use when the |
700 | not used for a while and timeouts should not be processed. |
702 | loop is not used for a while and timeouts should not be processed. |
701 | |
703 | |
702 | A typical use case would be an interactive program such as a game: When |
704 | A typical use case would be an interactive program such as a game: When |
703 | the user presses C<^Z> to suspend the game and resumes it an hour later it |
705 | the user presses C<^Z> to suspend the game and resumes it an hour later it |
704 | would be best to handle timeouts as if no time had actually passed while |
706 | would be best to handle timeouts as if no time had actually passed while |
705 | the program was suspended. This can be achieved by calling C<ev_suspend> |
707 | the program was suspended. This can be achieved by calling C<ev_suspend> |
… | |
… | |
716 | without a previous call to C<ev_suspend>. |
718 | without a previous call to C<ev_suspend>. |
717 | |
719 | |
718 | Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the |
720 | Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the |
719 | event loop time (see C<ev_now_update>). |
721 | event loop time (see C<ev_now_update>). |
720 | |
722 | |
721 | =item ev_loop (loop, int flags) |
723 | =item ev_run (loop, int flags) |
722 | |
724 | |
723 | Finally, this is it, the event handler. This function usually is called |
725 | Finally, this is it, the event handler. This function usually is called |
724 | after you have initialised all your watchers and you want to start |
726 | after you have initialised all your watchers and you want to start |
725 | handling events. |
727 | handling events. It will ask the operating system for any new events, call |
|
|
728 | the watcher callbacks, an then repeat the whole process indefinitely: This |
|
|
729 | is why event loops are called I<loops>. |
726 | |
730 | |
727 | If the flags argument is specified as C<0>, it will not return until |
731 | If the flags argument is specified as C<0>, it will keep handling events |
728 | either no event watchers are active anymore or C<ev_unloop> was called. |
732 | until either no event watchers are active anymore or C<ev_break> was |
|
|
733 | called. |
729 | |
734 | |
730 | Please note that an explicit C<ev_unloop> is usually better than |
735 | Please note that an explicit C<ev_break> is usually better than |
731 | relying on all watchers to be stopped when deciding when a program has |
736 | relying on all watchers to be stopped when deciding when a program has |
732 | finished (especially in interactive programs), but having a program |
737 | finished (especially in interactive programs), but having a program |
733 | that automatically loops as long as it has to and no longer by virtue |
738 | that automatically loops as long as it has to and no longer by virtue |
734 | of relying on its watchers stopping correctly, that is truly a thing of |
739 | of relying on its watchers stopping correctly, that is truly a thing of |
735 | beauty. |
740 | beauty. |
736 | |
741 | |
737 | A flags value of C<EVLOOP_NONBLOCK> will look for new events, will handle |
742 | A flags value of C<EVRUN_NOWAIT> will look for new events, will handle |
738 | those events and any already outstanding ones, but will not block your |
743 | those events and any already outstanding ones, but will not wait and |
739 | process in case there are no events and will return after one iteration of |
744 | block your process in case there are no events and will return after one |
740 | the loop. |
745 | iteration of the loop. This is sometimes useful to poll and handle new |
|
|
746 | events while doing lengthy calculations, to keep the program responsive. |
741 | |
747 | |
742 | A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if |
748 | A flags value of C<EVRUN_ONCE> will look for new events (waiting if |
743 | necessary) and will handle those and any already outstanding ones. It |
749 | necessary) and will handle those and any already outstanding ones. It |
744 | will block your process until at least one new event arrives (which could |
750 | will block your process until at least one new event arrives (which could |
745 | be an event internal to libev itself, so there is no guarantee that a |
751 | be an event internal to libev itself, so there is no guarantee that a |
746 | user-registered callback will be called), and will return after one |
752 | user-registered callback will be called), and will return after one |
747 | iteration of the loop. |
753 | iteration of the loop. |
748 | |
754 | |
749 | This is useful if you are waiting for some external event in conjunction |
755 | This is useful if you are waiting for some external event in conjunction |
750 | with something not expressible using other libev watchers (i.e. "roll your |
756 | with something not expressible using other libev watchers (i.e. "roll your |
751 | own C<ev_loop>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is |
757 | own C<ev_run>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is |
752 | usually a better approach for this kind of thing. |
758 | usually a better approach for this kind of thing. |
753 | |
759 | |
754 | Here are the gory details of what C<ev_loop> does: |
760 | Here are the gory details of what C<ev_run> does: |
755 | |
761 | |
|
|
762 | - Increment loop depth. |
|
|
763 | - Reset the ev_break status. |
756 | - Before the first iteration, call any pending watchers. |
764 | - Before the first iteration, call any pending watchers. |
|
|
765 | LOOP: |
757 | * If EVFLAG_FORKCHECK was used, check for a fork. |
766 | - If EVFLAG_FORKCHECK was used, check for a fork. |
758 | - If a fork was detected (by any means), queue and call all fork watchers. |
767 | - If a fork was detected (by any means), queue and call all fork watchers. |
759 | - Queue and call all prepare watchers. |
768 | - Queue and call all prepare watchers. |
|
|
769 | - If ev_break was called, goto FINISH. |
760 | - If we have been forked, detach and recreate the kernel state |
770 | - If we have been forked, detach and recreate the kernel state |
761 | as to not disturb the other process. |
771 | as to not disturb the other process. |
762 | - Update the kernel state with all outstanding changes. |
772 | - Update the kernel state with all outstanding changes. |
763 | - Update the "event loop time" (ev_now ()). |
773 | - Update the "event loop time" (ev_now ()). |
764 | - Calculate for how long to sleep or block, if at all |
774 | - Calculate for how long to sleep or block, if at all |
765 | (active idle watchers, EVLOOP_NONBLOCK or not having |
775 | (active idle watchers, EVRUN_NOWAIT or not having |
766 | any active watchers at all will result in not sleeping). |
776 | any active watchers at all will result in not sleeping). |
767 | - Sleep if the I/O and timer collect interval say so. |
777 | - Sleep if the I/O and timer collect interval say so. |
|
|
778 | - Increment loop iteration counter. |
768 | - Block the process, waiting for any events. |
779 | - Block the process, waiting for any events. |
769 | - Queue all outstanding I/O (fd) events. |
780 | - Queue all outstanding I/O (fd) events. |
770 | - Update the "event loop time" (ev_now ()), and do time jump adjustments. |
781 | - Update the "event loop time" (ev_now ()), and do time jump adjustments. |
771 | - Queue all expired timers. |
782 | - Queue all expired timers. |
772 | - Queue all expired periodics. |
783 | - Queue all expired periodics. |
773 | - Unless any events are pending now, queue all idle watchers. |
784 | - Queue all idle watchers with priority higher than that of pending events. |
774 | - Queue all check watchers. |
785 | - Queue all check watchers. |
775 | - Call all queued watchers in reverse order (i.e. check watchers first). |
786 | - Call all queued watchers in reverse order (i.e. check watchers first). |
776 | Signals and child watchers are implemented as I/O watchers, and will |
787 | Signals and child watchers are implemented as I/O watchers, and will |
777 | be handled here by queueing them when their watcher gets executed. |
788 | be handled here by queueing them when their watcher gets executed. |
778 | - If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
789 | - If ev_break has been called, or EVRUN_ONCE or EVRUN_NOWAIT |
779 | were used, or there are no active watchers, return, otherwise |
790 | were used, or there are no active watchers, goto FINISH, otherwise |
780 | continue with step *. |
791 | continue with step LOOP. |
|
|
792 | FINISH: |
|
|
793 | - Reset the ev_break status iff it was EVBREAK_ONE. |
|
|
794 | - Decrement the loop depth. |
|
|
795 | - Return. |
781 | |
796 | |
782 | Example: Queue some jobs and then loop until no events are outstanding |
797 | Example: Queue some jobs and then loop until no events are outstanding |
783 | anymore. |
798 | anymore. |
784 | |
799 | |
785 | ... queue jobs here, make sure they register event watchers as long |
800 | ... queue jobs here, make sure they register event watchers as long |
786 | ... as they still have work to do (even an idle watcher will do..) |
801 | ... as they still have work to do (even an idle watcher will do..) |
787 | ev_loop (my_loop, 0); |
802 | ev_run (my_loop, 0); |
788 | ... jobs done or somebody called unloop. yeah! |
803 | ... jobs done or somebody called unloop. yeah! |
789 | |
804 | |
790 | =item ev_unloop (loop, how) |
805 | =item ev_break (loop, how) |
791 | |
806 | |
792 | Can be used to make a call to C<ev_loop> return early (but only after it |
807 | Can be used to make a call to C<ev_run> return early (but only after it |
793 | has processed all outstanding events). The C<how> argument must be either |
808 | has processed all outstanding events). The C<how> argument must be either |
794 | C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or |
809 | C<EVBREAK_ONE>, which will make the innermost C<ev_run> call return, or |
795 | C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return. |
810 | C<EVBREAK_ALL>, which will make all nested C<ev_run> calls return. |
796 | |
811 | |
797 | This "unloop state" will be cleared when entering C<ev_loop> again. |
812 | This "unloop state" will be cleared when entering C<ev_run> again. |
798 | |
813 | |
799 | It is safe to call C<ev_unloop> from outside any C<ev_loop> calls. |
814 | It is safe to call C<ev_break> from outside any C<ev_run> calls. ##TODO## |
800 | |
815 | |
801 | =item ev_ref (loop) |
816 | =item ev_ref (loop) |
802 | |
817 | |
803 | =item ev_unref (loop) |
818 | =item ev_unref (loop) |
804 | |
819 | |
805 | Ref/unref can be used to add or remove a reference count on the event |
820 | Ref/unref can be used to add or remove a reference count on the event |
806 | loop: Every watcher keeps one reference, and as long as the reference |
821 | loop: Every watcher keeps one reference, and as long as the reference |
807 | count is nonzero, C<ev_loop> will not return on its own. |
822 | count is nonzero, C<ev_run> will not return on its own. |
808 | |
823 | |
809 | This is useful when you have a watcher that you never intend to |
824 | This is useful when you have a watcher that you never intend to |
810 | unregister, but that nevertheless should not keep C<ev_loop> from |
825 | unregister, but that nevertheless should not keep C<ev_run> from |
811 | returning. In such a case, call C<ev_unref> after starting, and C<ev_ref> |
826 | returning. In such a case, call C<ev_unref> after starting, and C<ev_ref> |
812 | before stopping it. |
827 | before stopping it. |
813 | |
828 | |
814 | As an example, libev itself uses this for its internal signal pipe: It |
829 | As an example, libev itself uses this for its internal signal pipe: It |
815 | is not visible to the libev user and should not keep C<ev_loop> from |
830 | is not visible to the libev user and should not keep C<ev_run> from |
816 | exiting if no event watchers registered by it are active. It is also an |
831 | exiting if no event watchers registered by it are active. It is also an |
817 | excellent way to do this for generic recurring timers or from within |
832 | excellent way to do this for generic recurring timers or from within |
818 | third-party libraries. Just remember to I<unref after start> and I<ref |
833 | third-party libraries. Just remember to I<unref after start> and I<ref |
819 | before stop> (but only if the watcher wasn't active before, or was active |
834 | before stop> (but only if the watcher wasn't active before, or was active |
820 | before, respectively. Note also that libev might stop watchers itself |
835 | before, respectively. Note also that libev might stop watchers itself |
821 | (e.g. non-repeating timers) in which case you have to C<ev_ref> |
836 | (e.g. non-repeating timers) in which case you have to C<ev_ref> |
822 | in the callback). |
837 | in the callback). |
823 | |
838 | |
824 | Example: Create a signal watcher, but keep it from keeping C<ev_loop> |
839 | Example: Create a signal watcher, but keep it from keeping C<ev_run> |
825 | running when nothing else is active. |
840 | running when nothing else is active. |
826 | |
841 | |
827 | ev_signal exitsig; |
842 | ev_signal exitsig; |
828 | ev_signal_init (&exitsig, sig_cb, SIGINT); |
843 | ev_signal_init (&exitsig, sig_cb, SIGINT); |
829 | ev_signal_start (loop, &exitsig); |
844 | ev_signal_start (loop, &exitsig); |
… | |
… | |
892 | ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01); |
907 | ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01); |
893 | |
908 | |
894 | =item ev_invoke_pending (loop) |
909 | =item ev_invoke_pending (loop) |
895 | |
910 | |
896 | This call will simply invoke all pending watchers while resetting their |
911 | This call will simply invoke all pending watchers while resetting their |
897 | pending state. Normally, C<ev_loop> does this automatically when required, |
912 | pending state. Normally, C<ev_run> does this automatically when required, |
898 | but when overriding the invoke callback this call comes handy. |
913 | but when overriding the invoke callback this call comes handy. This |
|
|
914 | function can be invoked from a watcher - this can be useful for example |
|
|
915 | when you want to do some lengthy calculation and want to pass further |
|
|
916 | event handling to another thread (you still have to make sure only one |
|
|
917 | thread executes within C<ev_invoke_pending> or C<ev_run> of course). |
899 | |
918 | |
900 | =item int ev_pending_count (loop) |
919 | =item int ev_pending_count (loop) |
901 | |
920 | |
902 | Returns the number of pending watchers - zero indicates that no watchers |
921 | Returns the number of pending watchers - zero indicates that no watchers |
903 | are pending. |
922 | are pending. |
904 | |
923 | |
905 | =item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P)) |
924 | =item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P)) |
906 | |
925 | |
907 | This overrides the invoke pending functionality of the loop: Instead of |
926 | This overrides the invoke pending functionality of the loop: Instead of |
908 | invoking all pending watchers when there are any, C<ev_loop> will call |
927 | invoking all pending watchers when there are any, C<ev_run> will call |
909 | this callback instead. This is useful, for example, when you want to |
928 | this callback instead. This is useful, for example, when you want to |
910 | invoke the actual watchers inside another context (another thread etc.). |
929 | invoke the actual watchers inside another context (another thread etc.). |
911 | |
930 | |
912 | If you want to reset the callback, use C<ev_invoke_pending> as new |
931 | If you want to reset the callback, use C<ev_invoke_pending> as new |
913 | callback. |
932 | callback. |
… | |
… | |
916 | |
935 | |
917 | Sometimes you want to share the same loop between multiple threads. This |
936 | Sometimes you want to share the same loop between multiple threads. This |
918 | can be done relatively simply by putting mutex_lock/unlock calls around |
937 | can be done relatively simply by putting mutex_lock/unlock calls around |
919 | each call to a libev function. |
938 | each call to a libev function. |
920 | |
939 | |
921 | However, C<ev_loop> can run an indefinite time, so it is not feasible to |
940 | However, C<ev_run> can run an indefinite time, so it is not feasible |
922 | wait for it to return. One way around this is to wake up the loop via |
941 | to wait for it to return. One way around this is to wake up the event |
923 | C<ev_unloop> and C<av_async_send>, another way is to set these I<release> |
942 | loop via C<ev_break> and C<av_async_send>, another way is to set these |
924 | and I<acquire> callbacks on the loop. |
943 | I<release> and I<acquire> callbacks on the loop. |
925 | |
944 | |
926 | When set, then C<release> will be called just before the thread is |
945 | When set, then C<release> will be called just before the thread is |
927 | suspended waiting for new events, and C<acquire> is called just |
946 | suspended waiting for new events, and C<acquire> is called just |
928 | afterwards. |
947 | afterwards. |
929 | |
948 | |
… | |
… | |
932 | |
951 | |
933 | While event loop modifications are allowed between invocations of |
952 | While event loop modifications are allowed between invocations of |
934 | C<release> and C<acquire> (that's their only purpose after all), no |
953 | C<release> and C<acquire> (that's their only purpose after all), no |
935 | modifications done will affect the event loop, i.e. adding watchers will |
954 | modifications done will affect the event loop, i.e. adding watchers will |
936 | have no effect on the set of file descriptors being watched, or the time |
955 | have no effect on the set of file descriptors being watched, or the time |
937 | waited. Use an C<ev_async> watcher to wake up C<ev_loop> when you want it |
956 | waited. Use an C<ev_async> watcher to wake up C<ev_run> when you want it |
938 | to take note of any changes you made. |
957 | to take note of any changes you made. |
939 | |
958 | |
940 | In theory, threads executing C<ev_loop> will be async-cancel safe between |
959 | In theory, threads executing C<ev_run> will be async-cancel safe between |
941 | invocations of C<release> and C<acquire>. |
960 | invocations of C<release> and C<acquire>. |
942 | |
961 | |
943 | See also the locking example in the C<THREADS> section later in this |
962 | See also the locking example in the C<THREADS> section later in this |
944 | document. |
963 | document. |
945 | |
964 | |
… | |
… | |
954 | These two functions can be used to associate arbitrary data with a loop, |
973 | These two functions can be used to associate arbitrary data with a loop, |
955 | and are intended solely for the C<invoke_pending_cb>, C<release> and |
974 | and are intended solely for the C<invoke_pending_cb>, C<release> and |
956 | C<acquire> callbacks described above, but of course can be (ab-)used for |
975 | C<acquire> callbacks described above, but of course can be (ab-)used for |
957 | any other purpose as well. |
976 | any other purpose as well. |
958 | |
977 | |
959 | =item ev_loop_verify (loop) |
978 | =item ev_verify (loop) |
960 | |
979 | |
961 | This function only does something when C<EV_VERIFY> support has been |
980 | This function only does something when C<EV_VERIFY> support has been |
962 | compiled in, which is the default for non-minimal builds. It tries to go |
981 | compiled in, which is the default for non-minimal builds. It tries to go |
963 | through all internal structures and checks them for validity. If anything |
982 | through all internal structures and checks them for validity. If anything |
964 | is found to be inconsistent, it will print an error message to standard |
983 | is found to be inconsistent, it will print an error message to standard |
… | |
… | |
975 | |
994 | |
976 | In the following description, uppercase C<TYPE> in names stands for the |
995 | In the following description, uppercase C<TYPE> in names stands for the |
977 | watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer |
996 | watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer |
978 | watchers and C<ev_io_start> for I/O watchers. |
997 | watchers and C<ev_io_start> for I/O watchers. |
979 | |
998 | |
980 | A watcher is a structure that you create and register to record your |
999 | A watcher is an opaque structure that you allocate and register to record |
981 | interest in some event. For instance, if you want to wait for STDIN to |
1000 | your interest in some event. To make a concrete example, imagine you want |
982 | become readable, you would create an C<ev_io> watcher for that: |
1001 | to wait for STDIN to become readable, you would create an C<ev_io> watcher |
|
|
1002 | for that: |
983 | |
1003 | |
984 | static void my_cb (struct ev_loop *loop, ev_io *w, int revents) |
1004 | static void my_cb (struct ev_loop *loop, ev_io *w, int revents) |
985 | { |
1005 | { |
986 | ev_io_stop (w); |
1006 | ev_io_stop (w); |
987 | ev_unloop (loop, EVUNLOOP_ALL); |
1007 | ev_break (loop, EVBREAK_ALL); |
988 | } |
1008 | } |
989 | |
1009 | |
990 | struct ev_loop *loop = ev_default_loop (0); |
1010 | struct ev_loop *loop = ev_default_loop (0); |
991 | |
1011 | |
992 | ev_io stdin_watcher; |
1012 | ev_io stdin_watcher; |
993 | |
1013 | |
994 | ev_init (&stdin_watcher, my_cb); |
1014 | ev_init (&stdin_watcher, my_cb); |
995 | ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ); |
1015 | ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ); |
996 | ev_io_start (loop, &stdin_watcher); |
1016 | ev_io_start (loop, &stdin_watcher); |
997 | |
1017 | |
998 | ev_loop (loop, 0); |
1018 | ev_run (loop, 0); |
999 | |
1019 | |
1000 | As you can see, you are responsible for allocating the memory for your |
1020 | As you can see, you are responsible for allocating the memory for your |
1001 | watcher structures (and it is I<usually> a bad idea to do this on the |
1021 | watcher structures (and it is I<usually> a bad idea to do this on the |
1002 | stack). |
1022 | stack). |
1003 | |
1023 | |
1004 | Each watcher has an associated watcher structure (called C<struct ev_TYPE> |
1024 | Each watcher has an associated watcher structure (called C<struct ev_TYPE> |
1005 | or simply C<ev_TYPE>, as typedefs are provided for all watcher structs). |
1025 | or simply C<ev_TYPE>, as typedefs are provided for all watcher structs). |
1006 | |
1026 | |
1007 | Each watcher structure must be initialised by a call to C<ev_init |
1027 | Each watcher structure must be initialised by a call to C<ev_init (watcher |
1008 | (watcher *, callback)>, which expects a callback to be provided. This |
1028 | *, callback)>, which expects a callback to be provided. This callback is |
1009 | callback gets invoked each time the event occurs (or, in the case of I/O |
1029 | invoked each time the event occurs (or, in the case of I/O watchers, each |
1010 | watchers, each time the event loop detects that the file descriptor given |
1030 | time the event loop detects that the file descriptor given is readable |
1011 | is readable and/or writable). |
1031 | and/or writable). |
1012 | |
1032 | |
1013 | Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >> |
1033 | Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >> |
1014 | macro to configure it, with arguments specific to the watcher type. There |
1034 | macro to configure it, with arguments specific to the watcher type. There |
1015 | is also a macro to combine initialisation and setting in one call: C<< |
1035 | is also a macro to combine initialisation and setting in one call: C<< |
1016 | ev_TYPE_init (watcher *, callback, ...) >>. |
1036 | ev_TYPE_init (watcher *, callback, ...) >>. |
… | |
… | |
1067 | |
1087 | |
1068 | =item C<EV_PREPARE> |
1088 | =item C<EV_PREPARE> |
1069 | |
1089 | |
1070 | =item C<EV_CHECK> |
1090 | =item C<EV_CHECK> |
1071 | |
1091 | |
1072 | All C<ev_prepare> watchers are invoked just I<before> C<ev_loop> starts |
1092 | All C<ev_prepare> watchers are invoked just I<before> C<ev_run> starts |
1073 | to gather new events, and all C<ev_check> watchers are invoked just after |
1093 | to gather new events, and all C<ev_check> watchers are invoked just after |
1074 | C<ev_loop> has gathered them, but before it invokes any callbacks for any |
1094 | C<ev_run> has gathered them, but before it invokes any callbacks for any |
1075 | received events. Callbacks of both watcher types can start and stop as |
1095 | received events. Callbacks of both watcher types can start and stop as |
1076 | many watchers as they want, and all of them will be taken into account |
1096 | many watchers as they want, and all of them will be taken into account |
1077 | (for example, a C<ev_prepare> watcher might start an idle watcher to keep |
1097 | (for example, a C<ev_prepare> watcher might start an idle watcher to keep |
1078 | C<ev_loop> from blocking). |
1098 | C<ev_run> from blocking). |
1079 | |
1099 | |
1080 | =item C<EV_EMBED> |
1100 | =item C<EV_EMBED> |
1081 | |
1101 | |
1082 | The embedded event loop specified in the C<ev_embed> watcher needs attention. |
1102 | The embedded event loop specified in the C<ev_embed> watcher needs attention. |
1083 | |
1103 | |
… | |
… | |
1111 | example it might indicate that a fd is readable or writable, and if your |
1131 | example it might indicate that a fd is readable or writable, and if your |
1112 | callbacks is well-written it can just attempt the operation and cope with |
1132 | callbacks is well-written it can just attempt the operation and cope with |
1113 | the error from read() or write(). This will not work in multi-threaded |
1133 | the error from read() or write(). This will not work in multi-threaded |
1114 | programs, though, as the fd could already be closed and reused for another |
1134 | programs, though, as the fd could already be closed and reused for another |
1115 | thing, so beware. |
1135 | thing, so beware. |
|
|
1136 | |
|
|
1137 | =back |
|
|
1138 | |
|
|
1139 | =head2 WATCHER STATES |
|
|
1140 | |
|
|
1141 | There are various watcher states mentioned throughout this manual - |
|
|
1142 | active, pending and so on. In this section these states and the rules to |
|
|
1143 | transition between them will be described in more detail - and while these |
|
|
1144 | rules might look complicated, they usually do "the right thing". |
|
|
1145 | |
|
|
1146 | =over 4 |
|
|
1147 | |
|
|
1148 | =item initialiased |
|
|
1149 | |
|
|
1150 | Before a watcher can be registered with the event looop it has to be |
|
|
1151 | initialised. This can be done with a call to C<ev_TYPE_init>, or calls to |
|
|
1152 | C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function. |
|
|
1153 | |
|
|
1154 | In this state it is simply some block of memory that is suitable for use |
|
|
1155 | in an event loop. It can be moved around, freed, reused etc. at will. |
|
|
1156 | |
|
|
1157 | =item started/running/active |
|
|
1158 | |
|
|
1159 | Once a watcher has been started with a call to C<ev_TYPE_start> it becomes |
|
|
1160 | property of the event loop, and is actively waiting for events. While in |
|
|
1161 | this state it cannot be accessed (except in a few documented ways), moved, |
|
|
1162 | freed or anything else - the only legal thing is to keep a pointer to it, |
|
|
1163 | and call libev functions on it that are documented to work on active watchers. |
|
|
1164 | |
|
|
1165 | =item pending |
|
|
1166 | |
|
|
1167 | If a watcher is active and libev determines that an event it is interested |
|
|
1168 | in has occurred (such as a timer expiring), it will become pending. It will |
|
|
1169 | stay in this pending state until either it is stopped or its callback is |
|
|
1170 | about to be invoked, so it is not normally pending inside the watcher |
|
|
1171 | callback. |
|
|
1172 | |
|
|
1173 | The watcher might or might not be active while it is pending (for example, |
|
|
1174 | an expired non-repeating timer can be pending but no longer active). If it |
|
|
1175 | is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>), |
|
|
1176 | but it is still property of the event loop at this time, so cannot be |
|
|
1177 | moved, freed or reused. And if it is active the rules described in the |
|
|
1178 | previous item still apply. |
|
|
1179 | |
|
|
1180 | It is also possible to feed an event on a watcher that is not active (e.g. |
|
|
1181 | via C<ev_feed_event>), in which case it becomes pending without being |
|
|
1182 | active. |
|
|
1183 | |
|
|
1184 | =item stopped |
|
|
1185 | |
|
|
1186 | A watcher can be stopped implicitly by libev (in which case it might still |
|
|
1187 | be pending), or explicitly by calling its C<ev_TYPE_stop> function. The |
|
|
1188 | latter will clear any pending state the watcher might be in, regardless |
|
|
1189 | of whether it was active or not, so stopping a watcher explicitly before |
|
|
1190 | freeing it is often a good idea. |
|
|
1191 | |
|
|
1192 | While stopped (and not pending) the watcher is essentially in the |
|
|
1193 | initialised state, that is it can be reused, moved, modified in any way |
|
|
1194 | you wish. |
1116 | |
1195 | |
1117 | =back |
1196 | =back |
1118 | |
1197 | |
1119 | =head2 GENERIC WATCHER FUNCTIONS |
1198 | =head2 GENERIC WATCHER FUNCTIONS |
1120 | |
1199 | |
… | |
… | |
1624 | ... |
1703 | ... |
1625 | struct ev_loop *loop = ev_default_init (0); |
1704 | struct ev_loop *loop = ev_default_init (0); |
1626 | ev_io stdin_readable; |
1705 | ev_io stdin_readable; |
1627 | ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
1706 | ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
1628 | ev_io_start (loop, &stdin_readable); |
1707 | ev_io_start (loop, &stdin_readable); |
1629 | ev_loop (loop, 0); |
1708 | ev_run (loop, 0); |
1630 | |
1709 | |
1631 | |
1710 | |
1632 | =head2 C<ev_timer> - relative and optionally repeating timeouts |
1711 | =head2 C<ev_timer> - relative and optionally repeating timeouts |
1633 | |
1712 | |
1634 | Timer watchers are simple relative timers that generate an event after a |
1713 | Timer watchers are simple relative timers that generate an event after a |
… | |
… | |
1643 | The callback is guaranteed to be invoked only I<after> its timeout has |
1722 | The callback is guaranteed to be invoked only I<after> its timeout has |
1644 | passed (not I<at>, so on systems with very low-resolution clocks this |
1723 | passed (not I<at>, so on systems with very low-resolution clocks this |
1645 | might introduce a small delay). If multiple timers become ready during the |
1724 | might introduce a small delay). If multiple timers become ready during the |
1646 | same loop iteration then the ones with earlier time-out values are invoked |
1725 | same loop iteration then the ones with earlier time-out values are invoked |
1647 | before ones of the same priority with later time-out values (but this is |
1726 | before ones of the same priority with later time-out values (but this is |
1648 | no longer true when a callback calls C<ev_loop> recursively). |
1727 | no longer true when a callback calls C<ev_run> recursively). |
1649 | |
1728 | |
1650 | =head3 Be smart about timeouts |
1729 | =head3 Be smart about timeouts |
1651 | |
1730 | |
1652 | Many real-world problems involve some kind of timeout, usually for error |
1731 | Many real-world problems involve some kind of timeout, usually for error |
1653 | recovery. A typical example is an HTTP request - if the other side hangs, |
1732 | recovery. A typical example is an HTTP request - if the other side hangs, |
… | |
… | |
1824 | |
1903 | |
1825 | =head3 The special problem of time updates |
1904 | =head3 The special problem of time updates |
1826 | |
1905 | |
1827 | Establishing the current time is a costly operation (it usually takes at |
1906 | Establishing the current time is a costly operation (it usually takes at |
1828 | least two system calls): EV therefore updates its idea of the current |
1907 | least two system calls): EV therefore updates its idea of the current |
1829 | time only before and after C<ev_loop> collects new events, which causes a |
1908 | time only before and after C<ev_run> collects new events, which causes a |
1830 | growing difference between C<ev_now ()> and C<ev_time ()> when handling |
1909 | growing difference between C<ev_now ()> and C<ev_time ()> when handling |
1831 | lots of events in one iteration. |
1910 | lots of events in one iteration. |
1832 | |
1911 | |
1833 | The relative timeouts are calculated relative to the C<ev_now ()> |
1912 | The relative timeouts are calculated relative to the C<ev_now ()> |
1834 | time. This is usually the right thing as this timestamp refers to the time |
1913 | time. This is usually the right thing as this timestamp refers to the time |
… | |
… | |
1951 | } |
2030 | } |
1952 | |
2031 | |
1953 | ev_timer mytimer; |
2032 | ev_timer mytimer; |
1954 | ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */ |
2033 | ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */ |
1955 | ev_timer_again (&mytimer); /* start timer */ |
2034 | ev_timer_again (&mytimer); /* start timer */ |
1956 | ev_loop (loop, 0); |
2035 | ev_run (loop, 0); |
1957 | |
2036 | |
1958 | // and in some piece of code that gets executed on any "activity": |
2037 | // and in some piece of code that gets executed on any "activity": |
1959 | // reset the timeout to start ticking again at 10 seconds |
2038 | // reset the timeout to start ticking again at 10 seconds |
1960 | ev_timer_again (&mytimer); |
2039 | ev_timer_again (&mytimer); |
1961 | |
2040 | |
… | |
… | |
1987 | |
2066 | |
1988 | As with timers, the callback is guaranteed to be invoked only when the |
2067 | As with timers, the callback is guaranteed to be invoked only when the |
1989 | point in time where it is supposed to trigger has passed. If multiple |
2068 | point in time where it is supposed to trigger has passed. If multiple |
1990 | timers become ready during the same loop iteration then the ones with |
2069 | timers become ready during the same loop iteration then the ones with |
1991 | earlier time-out values are invoked before ones with later time-out values |
2070 | earlier time-out values are invoked before ones with later time-out values |
1992 | (but this is no longer true when a callback calls C<ev_loop> recursively). |
2071 | (but this is no longer true when a callback calls C<ev_run> recursively). |
1993 | |
2072 | |
1994 | =head3 Watcher-Specific Functions and Data Members |
2073 | =head3 Watcher-Specific Functions and Data Members |
1995 | |
2074 | |
1996 | =over 4 |
2075 | =over 4 |
1997 | |
2076 | |
… | |
… | |
2235 | Example: Try to exit cleanly on SIGINT. |
2314 | Example: Try to exit cleanly on SIGINT. |
2236 | |
2315 | |
2237 | static void |
2316 | static void |
2238 | sigint_cb (struct ev_loop *loop, ev_signal *w, int revents) |
2317 | sigint_cb (struct ev_loop *loop, ev_signal *w, int revents) |
2239 | { |
2318 | { |
2240 | ev_unloop (loop, EVUNLOOP_ALL); |
2319 | ev_break (loop, EVBREAK_ALL); |
2241 | } |
2320 | } |
2242 | |
2321 | |
2243 | ev_signal signal_watcher; |
2322 | ev_signal signal_watcher; |
2244 | ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
2323 | ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
2245 | ev_signal_start (loop, &signal_watcher); |
2324 | ev_signal_start (loop, &signal_watcher); |
… | |
… | |
2631 | |
2710 | |
2632 | Prepare and check watchers are usually (but not always) used in pairs: |
2711 | Prepare and check watchers are usually (but not always) used in pairs: |
2633 | prepare watchers get invoked before the process blocks and check watchers |
2712 | prepare watchers get invoked before the process blocks and check watchers |
2634 | afterwards. |
2713 | afterwards. |
2635 | |
2714 | |
2636 | You I<must not> call C<ev_loop> or similar functions that enter |
2715 | You I<must not> call C<ev_run> or similar functions that enter |
2637 | the current event loop from either C<ev_prepare> or C<ev_check> |
2716 | the current event loop from either C<ev_prepare> or C<ev_check> |
2638 | watchers. Other loops than the current one are fine, however. The |
2717 | watchers. Other loops than the current one are fine, however. The |
2639 | rationale behind this is that you do not need to check for recursion in |
2718 | rationale behind this is that you do not need to check for recursion in |
2640 | those watchers, i.e. the sequence will always be C<ev_prepare>, blocking, |
2719 | those watchers, i.e. the sequence will always be C<ev_prepare>, blocking, |
2641 | C<ev_check> so if you have one watcher of each kind they will always be |
2720 | C<ev_check> so if you have one watcher of each kind they will always be |
… | |
… | |
2809 | |
2888 | |
2810 | if (timeout >= 0) |
2889 | if (timeout >= 0) |
2811 | // create/start timer |
2890 | // create/start timer |
2812 | |
2891 | |
2813 | // poll |
2892 | // poll |
2814 | ev_loop (EV_A_ 0); |
2893 | ev_run (EV_A_ 0); |
2815 | |
2894 | |
2816 | // stop timer again |
2895 | // stop timer again |
2817 | if (timeout >= 0) |
2896 | if (timeout >= 0) |
2818 | ev_timer_stop (EV_A_ &to); |
2897 | ev_timer_stop (EV_A_ &to); |
2819 | |
2898 | |
… | |
… | |
2897 | if you do not want that, you need to temporarily stop the embed watcher). |
2976 | if you do not want that, you need to temporarily stop the embed watcher). |
2898 | |
2977 | |
2899 | =item ev_embed_sweep (loop, ev_embed *) |
2978 | =item ev_embed_sweep (loop, ev_embed *) |
2900 | |
2979 | |
2901 | Make a single, non-blocking sweep over the embedded loop. This works |
2980 | Make a single, non-blocking sweep over the embedded loop. This works |
2902 | similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most |
2981 | similarly to C<ev_run (embedded_loop, EVRUN_NOWAIT)>, but in the most |
2903 | appropriate way for embedded loops. |
2982 | appropriate way for embedded loops. |
2904 | |
2983 | |
2905 | =item struct ev_loop *other [read-only] |
2984 | =item struct ev_loop *other [read-only] |
2906 | |
2985 | |
2907 | The embedded event loop. |
2986 | The embedded event loop. |
… | |
… | |
3013 | =back |
3092 | =back |
3014 | |
3093 | |
3015 | |
3094 | |
3016 | =head2 C<ev_async> - how to wake up an event loop |
3095 | =head2 C<ev_async> - how to wake up an event loop |
3017 | |
3096 | |
3018 | In general, you cannot use an C<ev_loop> from multiple threads or other |
3097 | In general, you cannot use an C<ev_run> from multiple threads or other |
3019 | asynchronous sources such as signal handlers (as opposed to multiple event |
3098 | asynchronous sources such as signal handlers (as opposed to multiple event |
3020 | loops - those are of course safe to use in different threads). |
3099 | loops - those are of course safe to use in different threads). |
3021 | |
3100 | |
3022 | Sometimes, however, you need to wake up an event loop you do not control, |
3101 | Sometimes, however, you need to wake up an event loop you do not control, |
3023 | for example because it belongs to another thread. This is what C<ev_async> |
3102 | for example because it belongs to another thread. This is what C<ev_async> |
… | |
… | |
3530 | loop argument"). The C<EV_A> form is used when this is the sole argument, |
3609 | loop argument"). The C<EV_A> form is used when this is the sole argument, |
3531 | C<EV_A_> is used when other arguments are following. Example: |
3610 | C<EV_A_> is used when other arguments are following. Example: |
3532 | |
3611 | |
3533 | ev_unref (EV_A); |
3612 | ev_unref (EV_A); |
3534 | ev_timer_add (EV_A_ watcher); |
3613 | ev_timer_add (EV_A_ watcher); |
3535 | ev_loop (EV_A_ 0); |
3614 | ev_run (EV_A_ 0); |
3536 | |
3615 | |
3537 | It assumes the variable C<loop> of type C<struct ev_loop *> is in scope, |
3616 | It assumes the variable C<loop> of type C<struct ev_loop *> is in scope, |
3538 | which is often provided by the following macro. |
3617 | which is often provided by the following macro. |
3539 | |
3618 | |
3540 | =item C<EV_P>, C<EV_P_> |
3619 | =item C<EV_P>, C<EV_P_> |
… | |
… | |
3580 | } |
3659 | } |
3581 | |
3660 | |
3582 | ev_check check; |
3661 | ev_check check; |
3583 | ev_check_init (&check, check_cb); |
3662 | ev_check_init (&check, check_cb); |
3584 | ev_check_start (EV_DEFAULT_ &check); |
3663 | ev_check_start (EV_DEFAULT_ &check); |
3585 | ev_loop (EV_DEFAULT_ 0); |
3664 | ev_run (EV_DEFAULT_ 0); |
3586 | |
3665 | |
3587 | =head1 EMBEDDING |
3666 | =head1 EMBEDDING |
3588 | |
3667 | |
3589 | Libev can (and often is) directly embedded into host |
3668 | Libev can (and often is) directly embedded into host |
3590 | applications. Examples of applications that embed it include the Deliantra |
3669 | applications. Examples of applications that embed it include the Deliantra |
… | |
… | |
3681 | to a compiled library. All other symbols change the ABI, which means all |
3760 | to a compiled library. All other symbols change the ABI, which means all |
3682 | users of libev and the libev code itself must be compiled with compatible |
3761 | users of libev and the libev code itself must be compiled with compatible |
3683 | settings. |
3762 | settings. |
3684 | |
3763 | |
3685 | =over 4 |
3764 | =over 4 |
|
|
3765 | |
|
|
3766 | =item EV_COMPAT3 (h) |
|
|
3767 | |
|
|
3768 | Backwards compatibility is a major concern for libev. This is why this |
|
|
3769 | release of libev comes with wrappers for the functions and symbols that |
|
|
3770 | have been renamed between libev version 3 and 4. |
|
|
3771 | |
|
|
3772 | You can disable these wrappers (to test compatibility with future |
|
|
3773 | versions) by defining C<EV_COMPAT3> to C<0> when compiling your |
|
|
3774 | sources. This has the additional advantage that you can drop the C<struct> |
|
|
3775 | from C<struct ev_loop> declarations, as libev will provide an C<ev_loop> |
|
|
3776 | typedef in that case. |
|
|
3777 | |
|
|
3778 | In some future version, the default for C<EV_COMPAT3> will become C<0>, |
|
|
3779 | and in some even more future version the compatibility code will be |
|
|
3780 | removed completely. |
3686 | |
3781 | |
3687 | =item EV_STANDALONE (h) |
3782 | =item EV_STANDALONE (h) |
3688 | |
3783 | |
3689 | Must always be C<1> if you do not use autoconf configuration, which |
3784 | Must always be C<1> if you do not use autoconf configuration, which |
3690 | keeps libev from including F<config.h>, and it also defines dummy |
3785 | keeps libev from including F<config.h>, and it also defines dummy |
… | |
… | |
4040 | The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it |
4135 | The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it |
4041 | will be C<0>. |
4136 | will be C<0>. |
4042 | |
4137 | |
4043 | =item EV_VERIFY |
4138 | =item EV_VERIFY |
4044 | |
4139 | |
4045 | Controls how much internal verification (see C<ev_loop_verify ()>) will |
4140 | Controls how much internal verification (see C<ev_verify ()>) will |
4046 | be done: If set to C<0>, no internal verification code will be compiled |
4141 | be done: If set to C<0>, no internal verification code will be compiled |
4047 | in. If set to C<1>, then verification code will be compiled in, but not |
4142 | in. If set to C<1>, then verification code will be compiled in, but not |
4048 | called. If set to C<2>, then the internal verification code will be |
4143 | called. If set to C<2>, then the internal verification code will be |
4049 | called once per loop, which can slow down libev. If set to C<3>, then the |
4144 | called once per loop, which can slow down libev. If set to C<3>, then the |
4050 | verification code will be called very frequently, which will slow down |
4145 | verification code will be called very frequently, which will slow down |
… | |
… | |
4265 | userdata *u = ev_userdata (EV_A); |
4360 | userdata *u = ev_userdata (EV_A); |
4266 | pthread_mutex_lock (&u->lock); |
4361 | pthread_mutex_lock (&u->lock); |
4267 | } |
4362 | } |
4268 | |
4363 | |
4269 | The event loop thread first acquires the mutex, and then jumps straight |
4364 | The event loop thread first acquires the mutex, and then jumps straight |
4270 | into C<ev_loop>: |
4365 | into C<ev_run>: |
4271 | |
4366 | |
4272 | void * |
4367 | void * |
4273 | l_run (void *thr_arg) |
4368 | l_run (void *thr_arg) |
4274 | { |
4369 | { |
4275 | struct ev_loop *loop = (struct ev_loop *)thr_arg; |
4370 | struct ev_loop *loop = (struct ev_loop *)thr_arg; |
4276 | |
4371 | |
4277 | l_acquire (EV_A); |
4372 | l_acquire (EV_A); |
4278 | pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0); |
4373 | pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0); |
4279 | ev_loop (EV_A_ 0); |
4374 | ev_run (EV_A_ 0); |
4280 | l_release (EV_A); |
4375 | l_release (EV_A); |
4281 | |
4376 | |
4282 | return 0; |
4377 | return 0; |
4283 | } |
4378 | } |
4284 | |
4379 | |
… | |
… | |
4336 | |
4431 | |
4337 | =head3 COROUTINES |
4432 | =head3 COROUTINES |
4338 | |
4433 | |
4339 | Libev is very accommodating to coroutines ("cooperative threads"): |
4434 | Libev is very accommodating to coroutines ("cooperative threads"): |
4340 | libev fully supports nesting calls to its functions from different |
4435 | libev fully supports nesting calls to its functions from different |
4341 | coroutines (e.g. you can call C<ev_loop> on the same loop from two |
4436 | coroutines (e.g. you can call C<ev_run> on the same loop from two |
4342 | different coroutines, and switch freely between both coroutines running |
4437 | different coroutines, and switch freely between both coroutines running |
4343 | the loop, as long as you don't confuse yourself). The only exception is |
4438 | the loop, as long as you don't confuse yourself). The only exception is |
4344 | that you must not do this from C<ev_periodic> reschedule callbacks. |
4439 | that you must not do this from C<ev_periodic> reschedule callbacks. |
4345 | |
4440 | |
4346 | Care has been taken to ensure that libev does not keep local state inside |
4441 | Care has been taken to ensure that libev does not keep local state inside |
4347 | C<ev_loop>, and other calls do not usually allow for coroutine switches as |
4442 | C<ev_run>, and other calls do not usually allow for coroutine switches as |
4348 | they do not call any callbacks. |
4443 | they do not call any callbacks. |
4349 | |
4444 | |
4350 | =head2 COMPILER WARNINGS |
4445 | =head2 COMPILER WARNINGS |
4351 | |
4446 | |
4352 | Depending on your compiler and compiler settings, you might get no or a |
4447 | Depending on your compiler and compiler settings, you might get no or a |
… | |
… | |
4436 | =head3 C<kqueue> is buggy |
4531 | =head3 C<kqueue> is buggy |
4437 | |
4532 | |
4438 | The kqueue syscall is broken in all known versions - most versions support |
4533 | The kqueue syscall is broken in all known versions - most versions support |
4439 | only sockets, many support pipes. |
4534 | only sockets, many support pipes. |
4440 | |
4535 | |
4441 | Libev tries to work around this by not using C<kqueue> by default on |
4536 | Libev tries to work around this by not using C<kqueue> by default on this |
4442 | this rotten platform, but of course you can still ask for it when creating |
4537 | rotten platform, but of course you can still ask for it when creating a |
4443 | a loop. |
4538 | loop - embedding a socket-only kqueue loop into a select-based one is |
|
|
4539 | probably going to work well. |
4444 | |
4540 | |
4445 | =head3 C<poll> is buggy |
4541 | =head3 C<poll> is buggy |
4446 | |
4542 | |
4447 | Instead of fixing C<kqueue>, Apple replaced their (working) C<poll> |
4543 | Instead of fixing C<kqueue>, Apple replaced their (working) C<poll> |
4448 | implementation by something calling C<kqueue> internally around the 10.5.6 |
4544 | implementation by something calling C<kqueue> internally around the 10.5.6 |
… | |
… | |
4467 | |
4563 | |
4468 | =head3 C<errno> reentrancy |
4564 | =head3 C<errno> reentrancy |
4469 | |
4565 | |
4470 | The default compile environment on Solaris is unfortunately so |
4566 | The default compile environment on Solaris is unfortunately so |
4471 | thread-unsafe that you can't even use components/libraries compiled |
4567 | thread-unsafe that you can't even use components/libraries compiled |
4472 | without C<-D_REENTRANT> (as long as they use C<errno>), which, of course, |
4568 | without C<-D_REENTRANT> in a threaded program, which, of course, isn't |
4473 | isn't defined by default. |
4569 | defined by default. A valid, if stupid, implementation choice. |
4474 | |
4570 | |
4475 | If you want to use libev in threaded environments you have to make sure |
4571 | If you want to use libev in threaded environments you have to make sure |
4476 | it's compiled with C<_REENTRANT> defined. |
4572 | it's compiled with C<_REENTRANT> defined. |
4477 | |
4573 | |
4478 | =head3 Event port backend |
4574 | =head3 Event port backend |
4479 | |
4575 | |
4480 | The scalable event interface for Solaris is called "event ports". Unfortunately, |
4576 | The scalable event interface for Solaris is called "event |
4481 | this mechanism is very buggy. If you run into high CPU usage, your program |
4577 | ports". Unfortunately, this mechanism is very buggy in all major |
|
|
4578 | releases. If you run into high CPU usage, your program freezes or you get |
4482 | freezes or you get a large number of spurious wakeups, make sure you have |
4579 | a large number of spurious wakeups, make sure you have all the relevant |
4483 | all the relevant and latest kernel patches applied. No, I don't know which |
4580 | and latest kernel patches applied. No, I don't know which ones, but there |
4484 | ones, but there are multiple ones. |
4581 | are multiple ones to apply, and afterwards, event ports actually work |
|
|
4582 | great. |
4485 | |
4583 | |
4486 | If you can't get it to work, you can try running the program by setting |
4584 | If you can't get it to work, you can try running the program by setting |
4487 | the environment variable C<LIBEV_FLAGS=3> to only allow C<poll> and |
4585 | the environment variable C<LIBEV_FLAGS=3> to only allow C<poll> and |
4488 | C<select> backends. |
4586 | C<select> backends. |
4489 | |
4587 | |
4490 | =head2 AIX POLL BUG |
4588 | =head2 AIX POLL BUG |
4491 | |
4589 | |
4492 | AIX unfortunately has a broken C<poll.h> header. Libev works around |
4590 | AIX unfortunately has a broken C<poll.h> header. Libev works around |
4493 | this by trying to avoid the poll backend altogether (i.e. it's not even |
4591 | this by trying to avoid the poll backend altogether (i.e. it's not even |
4494 | compiled in), which normally isn't a big problem as C<select> works fine |
4592 | compiled in), which normally isn't a big problem as C<select> works fine |
4495 | with large bitsets, and AIX is dead anyway. |
4593 | with large bitsets on AIX, and AIX is dead anyway. |
4496 | |
4594 | |
4497 | =head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS |
4595 | =head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS |
4498 | |
4596 | |
4499 | =head3 General issues |
4597 | =head3 General issues |
4500 | |
4598 | |
… | |
… | |
4637 | watchers. |
4735 | watchers. |
4638 | |
4736 | |
4639 | =item C<double> must hold a time value in seconds with enough accuracy |
4737 | =item C<double> must hold a time value in seconds with enough accuracy |
4640 | |
4738 | |
4641 | The type C<double> is used to represent timestamps. It is required to |
4739 | The type C<double> is used to represent timestamps. It is required to |
4642 | have at least 51 bits of mantissa (and 9 bits of exponent), which is good |
4740 | have at least 51 bits of mantissa (and 9 bits of exponent), which is |
4643 | enough for at least into the year 4000. This requirement is fulfilled by |
4741 | good enough for at least into the year 4000 with millisecond accuracy |
|
|
4742 | (the design goal for libev). This requirement is overfulfilled by |
4644 | implementations implementing IEEE 754, which is basically all existing |
4743 | implementations using IEEE 754, which is basically all existing ones. With |
4645 | ones. With IEEE 754 doubles, you get microsecond accuracy until at least |
4744 | IEEE 754 doubles, you get microsecond accuracy until at least 2200. |
4646 | 2200. |
|
|
4647 | |
4745 | |
4648 | =back |
4746 | =back |
4649 | |
4747 | |
4650 | If you know of other additional requirements drop me a note. |
4748 | If you know of other additional requirements drop me a note. |
4651 | |
4749 | |
… | |
… | |
4729 | compatibility, so most programs should still compile. Those might be |
4827 | compatibility, so most programs should still compile. Those might be |
4730 | removed in later versions of libev, so better update early than late. |
4828 | removed in later versions of libev, so better update early than late. |
4731 | |
4829 | |
4732 | =over 4 |
4830 | =over 4 |
4733 | |
4831 | |
4734 | =item C<ev_loop_count> renamed to C<ev_iteration> |
4832 | =item function/symbol renames |
4735 | |
4833 | |
4736 | =item C<ev_loop_depth> renamed to C<ev_depth> |
4834 | A number of functions and symbols have been renamed: |
4737 | |
4835 | |
4738 | =item C<ev_loop_verify> renamed to C<ev_verify> |
4836 | ev_loop => ev_run |
|
|
4837 | EVLOOP_NONBLOCK => EVRUN_NOWAIT |
|
|
4838 | EVLOOP_ONESHOT => EVRUN_ONCE |
|
|
4839 | |
|
|
4840 | ev_unloop => ev_break |
|
|
4841 | EVUNLOOP_CANCEL => EVBREAK_CANCEL |
|
|
4842 | EVUNLOOP_ONE => EVBREAK_ONE |
|
|
4843 | EVUNLOOP_ALL => EVBREAK_ALL |
|
|
4844 | |
|
|
4845 | EV_TIMEOUT => EV_TIMER |
|
|
4846 | |
|
|
4847 | ev_loop_count => ev_iteration |
|
|
4848 | ev_loop_depth => ev_depth |
|
|
4849 | ev_loop_verify => ev_verify |
4739 | |
4850 | |
4740 | Most functions working on C<struct ev_loop> objects don't have an |
4851 | Most functions working on C<struct ev_loop> objects don't have an |
4741 | C<ev_loop_> prefix, so it was removed. Note that C<ev_loop_fork> is |
4852 | C<ev_loop_> prefix, so it was removed; C<ev_loop>, C<ev_unloop> and |
|
|
4853 | associated constants have been renamed to not collide with the C<struct |
|
|
4854 | ev_loop> anymore and C<EV_TIMER> now follows the same naming scheme |
|
|
4855 | as all other watcher types. Note that C<ev_loop_fork> is still called |
4742 | still called C<ev_loop_fork> because it would otherwise clash with the |
4856 | C<ev_loop_fork> because it would otherwise clash with the C<ev_fork> |
4743 | C<ev_fork> typedef. |
4857 | typedef. |
4744 | |
4858 | |
4745 | =item C<EV_TIMEOUT> renamed to C<EV_TIMER> in C<revents> |
4859 | =item C<EV_COMPAT3> backwards compatibility mechanism |
4746 | |
4860 | |
4747 | This is a simple rename - all other watcher types use their name |
4861 | The backward compatibility mechanism can be controlled by |
4748 | as revents flag, and now C<ev_timer> does, too. |
4862 | C<EV_COMPAT3>. See L<PREPROCESSOR SYMBOLS/MACROS> in the L<EMBEDDING> |
4749 | |
4863 | section. |
4750 | Both C<EV_TIMER> and C<EV_TIMEOUT> symbols were present in 3.x versions |
|
|
4751 | and continue to be present for the foreseeable future, so this is mostly a |
|
|
4752 | documentation change. |
|
|
4753 | |
4864 | |
4754 | =item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES> |
4865 | =item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES> |
4755 | |
4866 | |
4756 | The preprocessor symbol C<EV_MINIMAL> has been replaced by a different |
4867 | The preprocessor symbol C<EV_MINIMAL> has been replaced by a different |
4757 | mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile |
4868 | mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile |
… | |
… | |
4764 | |
4875 | |
4765 | =over 4 |
4876 | =over 4 |
4766 | |
4877 | |
4767 | =item active |
4878 | =item active |
4768 | |
4879 | |
4769 | A watcher is active as long as it has been started (has been attached to |
4880 | A watcher is active as long as it has been started and not yet stopped. |
4770 | an event loop) but not yet stopped (disassociated from the event loop). |
4881 | See L<WATCHER STATES> for details. |
4771 | |
4882 | |
4772 | =item application |
4883 | =item application |
4773 | |
4884 | |
4774 | In this document, an application is whatever is using libev. |
4885 | In this document, an application is whatever is using libev. |
|
|
4886 | |
|
|
4887 | =item backend |
|
|
4888 | |
|
|
4889 | The part of the code dealing with the operating system interfaces. |
4775 | |
4890 | |
4776 | =item callback |
4891 | =item callback |
4777 | |
4892 | |
4778 | The address of a function that is called when some event has been |
4893 | The address of a function that is called when some event has been |
4779 | detected. Callbacks are being passed the event loop, the watcher that |
4894 | detected. Callbacks are being passed the event loop, the watcher that |
4780 | received the event, and the actual event bitset. |
4895 | received the event, and the actual event bitset. |
4781 | |
4896 | |
4782 | =item callback invocation |
4897 | =item callback/watcher invocation |
4783 | |
4898 | |
4784 | The act of calling the callback associated with a watcher. |
4899 | The act of calling the callback associated with a watcher. |
4785 | |
4900 | |
4786 | =item event |
4901 | =item event |
4787 | |
4902 | |
… | |
… | |
4806 | The model used to describe how an event loop handles and processes |
4921 | The model used to describe how an event loop handles and processes |
4807 | watchers and events. |
4922 | watchers and events. |
4808 | |
4923 | |
4809 | =item pending |
4924 | =item pending |
4810 | |
4925 | |
4811 | A watcher is pending as soon as the corresponding event has been detected, |
4926 | A watcher is pending as soon as the corresponding event has been |
4812 | and stops being pending as soon as the watcher will be invoked or its |
4927 | detected. See L<WATCHER STATES> for details. |
4813 | pending status is explicitly cleared by the application. |
|
|
4814 | |
|
|
4815 | A watcher can be pending, but not active. Stopping a watcher also clears |
|
|
4816 | its pending status. |
|
|
4817 | |
4928 | |
4818 | =item real time |
4929 | =item real time |
4819 | |
4930 | |
4820 | The physical time that is observed. It is apparently strictly monotonic :) |
4931 | The physical time that is observed. It is apparently strictly monotonic :) |
4821 | |
4932 | |
… | |
… | |
4828 | =item watcher |
4939 | =item watcher |
4829 | |
4940 | |
4830 | A data structure that describes interest in certain events. Watchers need |
4941 | A data structure that describes interest in certain events. Watchers need |
4831 | to be started (attached to an event loop) before they can receive events. |
4942 | to be started (attached to an event loop) before they can receive events. |
4832 | |
4943 | |
4833 | =item watcher invocation |
|
|
4834 | |
|
|
4835 | The act of calling the callback associated with a watcher. |
|
|
4836 | |
|
|
4837 | =back |
4944 | =back |
4838 | |
4945 | |
4839 | =head1 AUTHOR |
4946 | =head1 AUTHOR |
4840 | |
4947 | |
4841 | Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson. |
4948 | Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson. |